Effect of temperature on the spectrum of sulfur dioxide

1969 ◽  
Vol 47 (22) ◽  
pp. 4291-4292 ◽  
Author(s):  
J. Brown ◽  
George Burns
Keyword(s):  
Excited State ◽  
Sulfur Dioxide ◽  
Equilibrium Constant ◽  
Enthalpy Change ◽  
Ultraviolet Spectrum ◽  
Effect Of Temperature ◽  
Isomeric Form ◽  
Kcal Mole ◽  
Temperature Range

The effect of temperature on the ultraviolet spectrum of sulfur dioxide has been studied over the temperature range 20 to 1000 °C. The equilibrium constant for the reaction[Formula: see text]where (SO2) is an isomeric form or an excited state of sulfur dioxide, has been obtained at several temperatures. The enthalpy change for the transition was found to be 4.1 ± 0.4 kcal mole−1.

Mass spectrometric study of the reaction of BF3 with B2O3; the identification and heat of formation of B2OF4

1970 ◽  
Vol 48 (16) ◽  
pp. 2484-2487 ◽  
Author(s):  
D. R. Bidinosti ◽  
L. L. Coatsworth
Keyword(s):  
Temperature Dependence ◽  
Equilibrium Constant ◽  
Flow Reactor ◽  
Mass Spectrometric Study ◽  
Heat Of Formation ◽  
Enthalpy Change ◽  
Mass Spectrometric ◽  
Molecular Flow ◽  
Spectrometric Study ◽  
Kcal Mole

The reaction of BF3 with B2O3 in a molecular flow reactor has been studied with a mass spectrometer. Over the temperature range 930–1300 K the reaction has been found to produce B2OF4 with the stoichiometry[Formula: see text]From the temperature dependence of the equilibrium constant the enthalpy change for this reaction was determined to be 18.5 ± 3 kcal/mole and ΔHf0 (B2OF4) calculated to be −454 ± 2 kcal/mole at 1100 K.

Acetylene chemisorption at palladium: Effect of temperature and structure of the surface

1984 ◽  
Vol 49 (6) ◽  
pp. 1448-1458
Author(s):  
Josef Kopešťanský
Keyword(s):  
Work Function ◽  
Atomic Hydrogen ◽  
Effect Of Temperature ◽  
Thermally Stable ◽  
Template Effect ◽  
Temperature Range ◽  
Adsorbed Layers ◽  
Different Types ◽  
Adsorption Complexes ◽  
Low Coverage

The effect of temperature and structure of the palladium surfaces on acetylene chemisorption was studied along with the interaction of the adsorbed layers with molecular and atomic hydrogen. The work function changes were measured and combined with the volumetric measurements and analysis of the products. At temperature below 100 °C, acetylene is adsorbed almost without dissociation and forms at least two different types of thermally stable adsorption complexes. Acetylene adsorbed at 200 °C is partly decomposed, especially in the low coverage region. Besides the above mentioned effects, the template effect of adsorbed acetylene was studied in the temperature range from -80° to 25 °C. It has been shown that this effect is a typical phenomenon of the palladium-acetylene system which is not due to surface impurities.

Chemical equilibrium and chemical kinetics

2018 ◽  
Author(s):  
Dennis Sherwood ◽  
Paul Dalby
Keyword(s):  
Free Energy ◽  
Equilibrium Constant ◽  
Gibbs Free Energy ◽  
Chemical Kinetics ◽  
Chemical Equilibrium ◽  
First Principles ◽  
Effect Of Temperature ◽  
Total System ◽  
Free Energies

Building on the previous chapter, this chapter examines gas phase chemical equilibrium, and the equilibrium constant. This chapter takes a rigorous, yet very clear, ‘first principles’ approach, expressing the total Gibbs free energy of a reaction mixture at any time as the sum of the instantaneous Gibbs free energies of each component, as expressed in terms of the extent-of-reaction. The equilibrium reaction mixture is then defined as the point at which the total system Gibbs free energy is a minimum, from which concepts such as the equilibrium constant emerge. The chapter also explores the temperature dependence of equilibrium, this being one example of Le Chatelier’s principle. Finally, the chapter links thermodynamics to chemical kinetics by showing how the equilibrium constant is the ratio of the forward and backward rate constants. We also introduce the Arrhenius equation, closing with a discussion of the overall effect of temperature on chemical equilibrium.

A STUDY OF TAUTOMERISM IN CYCLIC β-DIKETONES BY PROTON MAGNETIC RESONANCE

1965 ◽  
Vol 43 (11) ◽  
pp. 3057-3062 ◽  
Author(s):  
Natsuko Cyr ◽  
Leonard W. Reeves
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Enthalpy Change ◽  
Enol Form ◽  
Proton Resonance ◽  
Kcal Mole ◽  
Intensity Measurements ◽  
Acetonitrile Solutions ◽  
Monomer Form

The keto–enol equilibrium of cyclohexane-1,3-dione in chloroform is best interpreted from proton resonance measurements as[Formula: see text]K1 and K2 may be separately determined from chemical shift measurements of the enol-OH proton and intensity measurements of peaks assigned to keto and enol forms. K1 and K2 are satisfactorily independent of concentrations except in very dilute solutions where intensity measurements become unreliable. The overall equilibrium constant K = K1 × K22 can be obtained for the same molecule in acetonitrile solutions where the enol monomer form is in very low concentration. 5,5′-Dimethylcyclohexane-1,3-dione in chloroform has less enol form than the unsubstituted molecule. The enthalpy change associated with 'K' for cyclohexane-1,3-dione in chloroform is 2.05 ± 0.5 kcal mole−1.

The dissolution of beryllia in molten alkali metal hydroxides

1965 ◽  
Vol 18 (11) ◽  
pp. 1719 ◽  
Author(s):  
ME Shying ◽  
RB Temple
Keyword(s):  
Alkali Metal ◽  
Water Vapour ◽  
Beryllium Oxide ◽  
Major Product ◽  
Kcal Mole ◽  
Metal Hydroxides ◽  
Temperature Range ◽  
Alkali Metal Hydroxides ◽  
Reversible Formation

Beryllium oxide shows a limited reversible solubility in molten alkali-metal hydroxides only when dissolved water vapour is present. The reaction taking place has been studied in detail. The results obtained are consistent with the reversible formation of the beryllate ion [Be(OH)4]2- as the major product, according to the overall equation BeO(solid) + H2O(dissolved) + 2OH- ↔ [Be(OH)4]2-(dissolved) The enthalpy of the reaction has been calculated to be 4.8 kcal/mole over the temperature range 240-510�.

THE EFFECT OF TEMPERATURE ON THE RATE AND VARIATION OF OPERCULAR MOVEMENT IN FUNDULUS DIAPHANUS DIAPHANUS

1947 ◽  
Vol 25d (2) ◽  
pp. 91-95
Author(s):  
Benjamin N. Kropp
Keyword(s):  
Constant Temperature ◽  
Beat Frequency ◽  
Nervous Activity ◽  
Respiratory Movement ◽  
Effect Of Temperature ◽  
Temperature Range ◽  
Sources Of Variation ◽  
Fundulus Diaphanus

The rates of opercular beat of 16 specimens of Fundulus diaphanus diaphanus were recorded over a temperature range from 4.3° to 17.5 °C. in order to determine how this respiratory movement varied with temperature and some of the sources of variation in rate. While the rate of beat varies directly as the temperature, over a period of several hours at any constant temperature continuous recordings of the rate show recurring cycles of rise and fall in beat frequency that are chiefly responsible for the scatter of the observations. Both the duration of a cycle and the limits of rise and fall for each cycle are definitely set by the temperature. The possible dependence of these phenomena upon central nervous activity is discussed.

Mitochondrial membrane fluorescence and temperature adaptation in Schistocephalus solidus (Cestoda: Pseudophyllidea)

Parasitology ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 131-135 ◽  
Author(s):  
R. W. Walker ◽  
J. Barrett
Keyword(s):  
Gasterosteus Aculeatus ◽  
Arrhenius Plot ◽  
Gallus Domesticus ◽  
Temperature Adaptation ◽  
Effect Of Temperature ◽  
Acclimation Temperature ◽  
Membrane Composition ◽  
Mitochondrial Membranes ◽  
Temperature Range ◽  
Schistocephalus Solidus

The fluorescent probe 1-anilino-8-naphthalene suiphonic acid (ANS) was used to investigate the effect of temperature on the physical state of the mitochondrial membranes of adult and larval schistocephalus solzdus together with that of their hosts Gasterosteus aculeatus and Gallus domesticus. Arrhenius plots of ANS/membrane fluorescence for S. solidus plerocercoids was linear over the temperature range 15 to 58 °C, while that for the adult was biphasic with a discontinuity at 39·9 °C. This was interpreted as a physical change which occurred in the adult membrane but not in the plerocercoid membrane and pointed to an alteration in membrane composition during infection. Gasierosteus aculeatus showed a linear Arrhenius plot for membrane fluorescence, irrespective of acclimation temperature. Gallus domesticus showed a discontinuity in the Arrhenius plot for membrane fluorescence at 46·9 °C, outside the normal physiological temperature range.

NQR Relaxation Studies on Halogenomethyl Groups in Halogenoacetates

1998 ◽  
Vol 53 (6-7) ◽  
pp. 480-483 ◽  
Author(s):  
Maria Zdanowska-Fnjczek
Keyword(s):  
Room Temperature ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Effect Of Temperature ◽  
Relaxation Theory ◽  
Temperature Range ◽  
Spin Lattice ◽  
Relaxation Studies

Abstract The effect of temperature on the chlorine NQR spin-lattice relaxation times in CsH(ClH2-CCOO)2 , KH(Cl3 CCOO) 2 and N(CH3)4 H(ClF2CCOO)2 has been studied in the temperature range 77 K to room temperature. The results were discussed on the basis of NQR relaxation theory.

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